This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
The following abbreviations that may be found in the specification and/or the drawing figures are defined as follows:    3GPP third generation partnership project    BS base station    BW bandwidth    DL downlink (eNB towards UE)    DRX discontinuous reception    eNB E-UTRAN Node B (evolved Node B)    EDGE enhanced data rates for GSM evolution or enhanced GPRS    EPC evolved packet core    E-UTRAN evolved UTRAN (LTE)    FDMA frequency division multiple access    GERAN GSM/EDGE radio access network    GPRS general packet radio services    GSM global system for mobile communication    IMSI international mobile subscriber identity    LTE long term evolution of UTRAN (E-UTRAN)    MAC medium access control (layer 2, L2)    MM/MME mobility management/mobility management entity    Node B base station    OFDMA orthogonal frequency division multiple access    O&M operations and maintenance    PCCH physical control channel    PDCCH physical downlink control channel    PDCP packet data convergence protocol    PHY physical (layer 1, L1)    PRB physical resource block    P-RNTI paging radio network temporary identifier (paging group identifier)    RLC radio link control    RRC radio resource control    RRM radio resource management    SFN system frame number    S-GW serving gateway    SC-FDMA single carrier, frequency division multiple access    UE user equipment, such as a mobile station or mobile terminal    UL uplink (UE towards eNB)    UTRAN universal terrestrial radio access network
A communication system known as evolved UTRAN (E-UTRAN, also referred to as UTRAN-LTE or as E-UTRA) is currently under development within the 3GPP. As presently specified the DL access technique will be OFDMA, and the UL access technique will be SC-FDMA.
One specification of interest is 3GPP TS 36.300, V8.3.0 (2007-12), 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Access Network (E-UTRAN); Overall description; Stage 2 (Release 8).
FIG. 1 reproduces FIG. 4.1 of 3GPP TS 36.300, and shows the overall architecture of the E-UTRAN system 2. The E-UTRAN system 2 includes eNBs 3, providing the E-UTRAN user plane (PDCP/RLC/MAC/PHY) and control plane (RRC) protocol terminations towards the UE (not shown). The eNBs 3 are interconnected with each other by means of an X2 interface. The eNBs 3 are also connected by means of an S1 interface to an EPC, more specifically to a MME by means of a S1 MME interface and to a S-GW by means of a S1-U interface (MME/S-GW 4). The S1 interface supports a many-to-many relationship between MMEs/S-GWs and eNBs.
The eNB hosts the following functions:                functions for RRM: RRC, Radio Admission Control, Connection Mobility Control, Dynamic allocation of resources to UEs in both UL and DL (scheduling);        IP header compression and encryption of the user data stream;        selection of a MME at UE attachment;        routing of User Plane data towards the EPC (MME/S-GW);        scheduling and transmission of paging messages (originated from the MME);        scheduling and transmission of broadcast information (originated from the MME or O&M); and        a measurement and measurement reporting configuration for mobility and scheduling.        
Another specification of interest herein is 3GPP TS 36.304, V8.0.0 (2008-02), 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); User Equipment (UE) procedures in idle mode (Release 8), as is a Change Request related thereto: R2-081137, 3GPP TSG_RAN WG2#61 meeting, Sorrento, Italy, 11-15 Feb. 2008.
An issue that arises with respect to the existing specifications is that the use of a UE-specific DRX may result in problems related to concentrating too many UEs in the same radio frames (e.g., for purposes of paging).
Paging may generally be seen to correspond to a UE monitoring one or more DL subframes in order to receive a P-RNTI (i.e. one or more paging messages having a P-RNTI assigned to the UE) transmitted on the PDCCH.
Following 3GPP TS 36.304 V8.0.0, for subclause 7.1 it was proposed that the paging DRX calculation be performed as follows:
Radio Frame of the paging occasion is given by the following equation:SFN mod T=(T div N)*(UE—ID mod N)
In the above equation, note that: T is the paging DRX (non-UE-specific), for example, as measured in a number of radio frames. N is the number of paging groups. “div” stands for a division operator/operation. “mod” stands for a modulus operator/operation.
It was also proposed that the paging subframe used from the subframe pattern defined in subclause 7.2 be derived from following calculation:Subframe from pattern=(UE—ID/N)mod Nsubframes_per_radioframe
However, this proposed procedure has a problem at least when the UE (multiple UEs) operates with UE-specific DRX. For example, consider broadcast parameters: T=128 (radio frames), N=64 and the UE has Tue (UE-specific paging DRX) of 64. The result is that those UEs with these specific UE DRX parameters will be concentrated (bunched) to specific paging occasions. This is true since the number of paging groups is the same for the UE-specific DRX case (64 in this example) as for UEs with broadcast paging DRX (128 in this case), e.g., UEs with paging DRX=64, and paging groups 64 have one paging group every radio frame. However, for non UE specific DRX (128) UEs there will exist a paging group only in every other radio frame. The end result of this will be more UEs clustered or bunched in every other radio frame, even though the intention would be to uniformly distribute UEs over the paging occasions. Reference in this regard may be made to FIG. 3. That is, FIG. 3 shows the undesirable clustering of UEs in certain paging occasions, which is a result of the conventional approach to providing UE-specific DRX.